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Old Nov 05, 2011, 08:11 PM
Not as Good as The Kid
Aeroplayin's Avatar
South Pasadena, FL
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Originally Posted by Tom K. View Post
Really? Cool!



Hmm... I'll have to re-do my thrust check if I get a chance tomorrow (fish scale test). Thanks for clarifying.

--Tom K.
We didn't do the digital scale test on the 2820-680 or the 630, so the numbers you remember were for something else. We did calculate static thrust to 6.7 though for the 680 (683Kv) on the 14x7.

We also now have the 14x7 Xoar to test on both motors against the 14x7 APC so stay tuned.
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Old Nov 05, 2011, 08:12 PM
Facts, Logic, 3D
Tom K.'s Avatar
Florida
Joined Nov 2010
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Quote:
Originally Posted by Aeroplayin View Post
We didn't do the digital scale test on the 2820-680 or the 630, so the numbers you remember were for something else. We did calculate static thrust to 6.7 though for the 680 (683Kv) on the 14x7.
Oh... whoops Then what was pulling 10lbs? lol

--Tom K.
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Old Nov 05, 2011, 08:26 PM
VOLTS > AMPS
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United States, MN, Buffalo
Joined Jul 2011
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http://www.youtube.com/watch?v=jE5y9...e_gdata_player

Hey guys I was testing stuff out tonight when I found out my rpm sensor was working at the field. Why am I hearing a sound like a rubbing? Ignore the high pitch sound the motor makes, beneath that there is a repeating sound. The motors brand new basically with four flights on it and it just started today. Removing the sensor did nothing
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Old Nov 05, 2011, 08:35 PM
3D Hack
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United States, IL, Glen Carbon
Joined Jul 2010
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Quote:
Originally Posted by stgdz View Post
http://www.youtube.com/watch?v=jE5y9...e_gdata_player

Hey guys I was testing stuff out tonight when I found out my rpm sensor was working at the field. Why am I hearing a sound like a rubbing? Ignore the high pitch sound the motor makes, beneath that there is a repeating sound. The motors brand new basically with four flights on it and it just started today. Removing the sensor did nothing
When you put the collar on the rear shaft, did you check to make sure that it was not rubbing the X-mount?

There is a sweet spot (no rubbing) that can be found by rotating the X-mount 90* when you are attaching it to the motor.

That's all I can think of except for the motor itself having an internal issue.

JC
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Old Nov 05, 2011, 10:15 PM
VOLTS > AMPS
stgdz's Avatar
United States, MN, Buffalo
Joined Jul 2011
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yeah I checked the collar, no rubbing its centered and all good. I tried a little oil but that didn't work. It sounds like it is coming from the front shaft bearing.

I am going to PM and e-mail EF and see what they say.
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Old Nov 05, 2011, 10:40 PM
3D Hack
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United States, IL, Glen Carbon
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Originally Posted by stgdz View Post
yeah I checked the collar, no rubbing its centered and all good. I tried a little oil but that didn't work. It sounds like it is coming from the front shaft bearing.

I am going to PM and e-mail EF and see what they say.
Front bearing - That would be a bummer...

Did you double check the collar? I had one on my 48" 300 EXP that I swore was fine out it rubbed after I had it buttoned in the plane.

Might double check by taking it off and checking the motor without it.

Just a thought.

JC
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Old Nov 05, 2011, 10:47 PM
Facts, Logic, 3D
Tom K.'s Avatar
Florida
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I remember the first time I flew a 48" EXP. It was my friend's 48" Extra EXP running 4S on the Torque setup. It was making a weird noise (different from the above) and I asked him if it was normal. He said, "Yeah, I think." So, while in a KE spin... the sound turned into a terrible grinding screeching horrific sound! I killed the power and glided it in. It threw a magnet. He called up Extreme Flight and sent it back and got a new one in the mail a little while later. Extreme Flight made it right. It just goes to show you're bound to have some losses in a big operation. Even though the motor died that flight, it definately gave me the final push to buy my first EXP... the 48" Extra with the torque setup. I keep wanting to bring that out to the field, but my Edge keeps on winning the coin toss.

--Tom K.
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Old Nov 06, 2011, 09:07 AM
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United States, SC, Pawleys Island
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Originally Posted by leespaddock View Post
Dead, Here is an idea take it for what it is worth. Not sure what thread tools you have as the orginal author of how much effort it would take to maintain.

Image that at the very front of this thread each EF plane discussed has a power system summary. That way anyone curious could look at the first page or so and see what most people are running (Motor, ESC, LIPo, Prop) for a given airplane. It would be kind of a contributor updatable front sort of like a powersystem wikiepedia.

It would look something like this:
60" Edge EXP
Motors - Torque xyz-123 / Motofly abc-456
ESC - Airboss 80A / Castle Ice 100A
LIPO - Nanotech 3300 6S 45/90c / Sky 3600 6S 30/60c
Prop - 15x6 / 15x7 APC E / Xoar PJN

Just trying to take this awesome thread to the next level.
Lee
Weird, I was just thinking about the same this morning. Not sure the easiest way to do it.... I could just start editing my first post and making it longer although I don't know if there is a limit on post length? I would have to maintain it for sure.

I will give it a try....
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Old Nov 06, 2011, 09:31 AM
Facts, Logic, 3D
Tom K.'s Avatar
Florida
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No limit. I've seen Doc Austin write up sport reports in here lol.

--Tom K.
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Old Nov 06, 2011, 09:29 PM
c/f
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this is a subject I have been wanting to start since spending 4 days exclusive with TEAM EF at e-week. The thing was they were flying a Telink 24-26 oz model with an
APC 10X4.7 SF at around 325watts.

I have been flying a very similiar planform and weight model with a APC E 11X6 around 300 watts. So after I got home I bumped the prop down to the APC 10X4.7 and bumped up the KV with an additional cell and WOW 400 watts and this plane has transformed from ho hum to WOW in 3D performance.

So my idea was to start a thread of the various EF models, what is the best 3D prop and how many watts are you putting in to it. You see HERCdrv?? tells me he snaps blades inflight and is very particular as to what prop he chooses, he actually says he cannot use some Xoar electrics as an example, of input variances.

You see this is not a motor question what so ever it really is what prop and how many watts in too it, consider this, IMHO a motor is nothing more than a convertor, the battery is the horsepower, in my world I use a 10gram battery weight will net me 25watts usable power. I will then adjust KV and cellcounts to get to the needed watts into a given prop.

In general I will pay whatever it takes to get a motor gram weight down for a given watt rating. Since returning from E-week I started my motor search to power an EF 48" Edge I bought @ E-week and it looks as if the torques @ 148G are a bit porky, and a Motrolfly around 97-121oz may actually work and quite a few in between with the 3DHS 130G seeing high marks.

Since I am taking Hercs advice of the APC E12X6 @ 600 watts this means I will be gearing up for a battery weight penalty of 240-250 grams.

So what do you think of a prop/watts spreadsheet / vote for each EF model?? The winner is really at the sticks in the air and not on a static bench meter. .02
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Old Nov 06, 2011, 09:44 PM
Facts, Logic, 3D
Tom K.'s Avatar
Florida
Joined Nov 2010
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Very interesting c/f. Just for some input for your decision, I've flown the Torque motor and the Motrolfly motor (Torque in my 48" Extra and Motrolfly in my 48" Edge) and I prefer the power and thrust the Motrolfly produces. The faster spinning 12x6 on the Torque and the slower spinning 14x7 on the Motrolfly produce similar prop speeds, but the lower kv (still on 4S) with the Motrolfly seems to produce more thrust as the prop doesn't stall as easily. Also, I get faster pullout with the Motrolfly and a wider column of air flowing over the plane during high alpha 3D maneuvers, leading to more precise control.

However, the Torque motor works well also. Very good for high speed, and it doesn't make as much noise when you do throttle-on spins as the Motrolfly with the bigger prop does.

--Tom K.
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Old Nov 06, 2011, 09:46 PM
Not as Good as The Kid
Aeroplayin's Avatar
South Pasadena, FL
Joined Sep 2009
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Originally Posted by dead View Post
Weird, I was just thinking about the same this morning. Not sure the easiest way to do it.... I could just start editing my first post and making it longer although I don't know if there is a limit on post length? I would have to maintain it for sure.

I will give it a try....
One of the things we can do is use the RC Web Club Web site to maintain a document library and refer to it from here. I can manage the documents so they are all in one place, on one page, all the time, and we can store them in chronological order. Let me know if this sounds like something that could help.
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Old Nov 06, 2011, 10:34 PM
Not as Good as The Kid
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I also want to clarify something about my analysis...

The prop constant I established created a calculative relationship between the power system and the various propellers of the same length and pitch. By using the pK value in the Watts formula I am able to make every variable from Lee’s data fall in line: Watts = ((Prop Constant) * (Prop Pitch) * (PRM ^3)) * (Prop Diameter ^4)

What this means for me is that, for example, the 15x8 APC propeller, on a 500Kv Torque motor will…

Spin at the rate of 8,560 calculated AND measured RPMs
And deliver 1431 calculated And measured Watts
At 65.3 calculated AND measured Amps
On 21.91 calculated AND measured volts
When the pK is 1.395, if the Xoar is…

Spinning 8,507 calculated AND measured RPMs
And delivering 1532 calculated AND measured Watts
At 69.5 calculated AND measured Amps
On 22.04 calculated AND measured volts
When the pK value is 1.521

This may seems a bit confusing, but the main idea is that all the numbers that were measured in Lee’s test of the APC are right in line with all the numbers that are calculated in all formulas used to determine and validate for Watts, Amps, volts, RPMs, etc, when the relative pK values are used.

APC Watts: 1431 = ((1.395) * (0.67) * (8.560 ^3)) * 1.25 ^4)
APC Amps = 1431W / 21.91v = 65.3A

Xoar Watts: 1535 = ((1.521) * (.067) * (8.507 ^3)) * 1.25 ^4)
Xoar Amps = 1535W / 22.04x = 69.5A

The same values result from the calculations as appear in Lee's measurements as long as the pK values are plugged into the formula, and we all know that every propeller has a different prop constant.

The challenge for all of us, and the initial focus of any ongoing analysis in this thread, I feel, will be to put this all to the test again in order to explain the contrary observations we have heard from people who have compared the APC and Xoar in the air -- APC with more Watts and Amps.

We should try to establish this conclusively. My 15x8 and 16x8 tests will be coming soon, along with some video evidence, since the props have now arrived from Lee and the rest were bought from Graves RC. I now also have a 14x7 Xoar to compare on the Motrolfly 2820-680 against the 14x7 APC on the 48 inch Edge. I can also get a 12x6 Xoar to compare on the Torque 820Kv motor with the 12x6 APC.
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Old Nov 06, 2011, 10:35 PM
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leespaddock's Avatar
USA, WA, Redmond
Joined Aug 2010
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Quote:
Originally Posted by c/f View Post
this is a subject I have been wanting to start since spending 4 days exclusive with TEAM EF at e-week. The thing was they were flying a Telink 24-26 oz model with an
APC 10X4.7 SF at around 325watts.

I have been flying a very similiar planform and weight model with a APC E 11X6 around 300 watts. So after I got home I bumped the prop down to the APC 10X4.7 and bumped up the KV with an additional cell and WOW 400 watts and this plane has transformed from ho hum to WOW in 3D performance.

So my idea was to start a thread of the various EF models, what is the best 3D prop and how many watts are you putting in to it. You see HERCdrv?? tells me he snaps blades inflight and is very particular as to what prop he chooses, he actually says he cannot use some Xoar electrics as an example, of input variances.

You see this is not a motor question what so ever it really is what prop and how many watts in too it, consider this, IMHO a motor is nothing more than a convertor, the battery is the horsepower, in my world I use a 10gram battery weight will net me 25watts usable power. I will then adjust KV and cellcounts to get to the needed watts into a given prop.

In general I will pay whatever it takes to get a motor gram weight down for a given watt rating. Since returning from E-week I started my motor search to power an EF 48" Edge I bought @ E-week and it looks as if the torques @ 148G are a bit porky, and a Motrolfly around 97-121oz may actually work and quite a few in between with the 3DHS 130G seeing high marks.

Since I am taking Hercs advice of the APC E12X6 @ 600 watts this means I will be gearing up for a battery weight penalty of 240-250 grams.

So what do you think of a prop/watts spreadsheet / vote for each EF model?? The winner is really at the sticks in the air and not on a static bench meter. .02
Good insight. I think this forum is headed in that very direction. I also appears that many people have been hoping and wishing for a thread just like this one. Eventually seperate sections / posts for each EF Plane. Measurable Data, Subjective Feel and Owners recommendation for each plane. Agreed there is a magic prop, esc, lipo and motor combination for a particular flying style and plane. I see EF continuing to do the major upfront research and it will be up to the flow down owners to experiment and refine from EF's initial recommendation. EF doesn't have the time to test every imaginable combo, however all of the EF plane owners do and that is how we together will crack the magic power system code for each plane. Just my thoughts.

Really Herc snaps props mid-air, sounds more like an urban legend to me. No offense to Herc and his mega agressive flying style. The prop in question has to have taken a few ground hits or been flown alot and I mean alot of 3D too create the kind of stress fractures and imbalance needed to break a prop mid-air. However if a paticular prop is blowing apart in the air after a certain flying duration that is great info to share with everyone. It is not unreasonable to think there is a flying time limit for any prop not unlike any other part of an aircraft large or small, manned or unmanned.
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Old Nov 06, 2011, 10:42 PM
Not as Good as The Kid
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Joined Sep 2009
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Just remember that Watts at the meter may not be telling the whole story and can be representing a segment of the load that is not going to power the prop. If you are over-propped, this meter reading can be an enigma.
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